Granite lobster is a level 74 Summoning familiar. It is summoned using a granite lobster pouch. The granite lobster can be used for the following things:

Combat: It has a combat level of 88 and provides Defence experience when it deals damage. In addition, its scroll, Crushing Claw, may inflict up to 964 life points' damage and temporarily decrease an opponent's Defence by five levels.

Fishing: It increases the player's Fishing level by 4. However, this boost is invisible. It does not grant abilities above the player's level (e.g., the ability to catch new kinds of fish). It does, however, increase the success rate of catching fish. Because of its large invisible boost, the granite lobster is fairly popular among players training fishing.

Forager: While the player is fishing, this familiar can produce raw swordfish and raw sharks, even if the player does not have the necessary level to catch these fish. It also gives the player 10% of the experience for catching the foraged items. It can hold up to 30 of its foraged items in its own inventory. It appears to collect the highest quantity of fish if the player is fishing sharks. One granite lobster often generates 3-13 swordfish and 3-13 sharks, giving 10 xp for each swordfish and 11 xp for each shark foraged.

Crushing claw is the special of the granite lobster, activated by a Crushing claw scroll. It may inflict up to 140 life points of magic damage and temporarily decrease an opponent's Defence by five levels.

As of 3 March 2010, any kind of granite can be used to create a granite lobster pouch. Before this update, only the 500g unit could be used.

At level 78 or above, a player can make over 400 of these pouches in one trip. This can be done by going to Bogrog with 5 kg granite chunks. The player then chisels the granite into pieces, makes pouches, and swap them for shards. It's a good idea to have a Beast of Burden familiar, however, so you can store the larger pieces of granite. Otherwise, they could end up being converted into pouches.

Excess amount of pouches and scrolls obtained through training can easily be redeemed for money. With 78 summoning, players trade in the pouches and scrolls to Bogrog and sell the shards to the pet store owner in Yanille. Players may also sell the pouches and scrolls in the Grand Exchange as they seem to be in high demand.